A gas meter device has been proposed which identifies which gas appliance starts to be used based on a flow rate change in gas flowing in a pipe. For example, PTL 1 below discloses a gas meter device in which a gas flow rate is measured at a prescribed time interval and a change pattern of an obtained flow rate value is compared with a change pattern of a flow rate value previously obtained for each gas appliance so as to discriminate the gas appliance which starts to be used. More specifically, the gas meter device disclosed in PTL 1 below converts a change amount of the gas flow rate obtained at each prescribed time interval into a corresponding code, and compares an obtained code string with a characteristic code string previously obtained for each gas appliance, thereby discriminating the gas appliance. PTL 1 has proposed to improve accuracy in discriminating the gas appliance as follows. In order to discriminate the gas appliance, in addition to the comparison of the code string, the flow rate indicating a characteristic of the gas appliance is further used, such as the flow rate during a slow ignition operation in a gas fan heater, for example. For reference, all disclosure contents of PTL 1 are incorporated herein by reference.